Alternative to poppler for converting a pdf document to QImage

jsulm

Did you check:

franco.amato

@jsulm said in Alternative to poppler for converting a pdf document to QImage:

Did you check:

https://doc.qt.io/qt-6/qtpdf-module.html - especially https://doc.qt.io/qt-6/qpdfdocument.html#render
Thank you.
I need to specify the resolution of 500 dpi and I don't understand how with the qpdfdocument. Do you know how?

ChrisW67

@franco-amato said in Alternative to poppler for converting a pdf document to QImage:

I need to specify the resolution of 500 dpi and I don't understand how with the qpdfdocument. Do you know how?

Does this work? Render the document page to a QImage of whatever pixel size corresponds to the desired (notional) physical size, set the notional X and Y pixels-per-metre on the image, and save the image. 500 DPI ~ 19685 PPM.
QImage::setDotsPerMeterX and
QImage::setDotsPerMeterY

franco.amato

It seems that the QPdfDocument is not available for Qt5 (that I am using for the development). The Qt documentation seems wrong

Christian Ehrlicher

QPdfDocument is available in Qt5 since Qt5.10 as you can see in the documentation: https://doc.qt.io/qt-5/qpdfdocument.html

franco.amato

I tried to include the QPdfDocument header file and it's not recognized

JoeCFD

@franco-amato did you install pdf module? Which Qt version are you using?

Christian Ehrlicher

@franco-amato then you did not install the QtPdf module or it's development package.

jsulm

@franco-amato said in Alternative to poppler for converting a pdf document to QImage:

I tried to include the QPdfDocument header file and it's not recognized

Did you add "QT += pdf" to your pro file?
Or

find_package(Qt5 COMPONENTS Pdf REQUIRED)
target_link_libraries(mytarget Qt5::Pdf)

to your CMakeLists.txt file?

franco.amato

It seems that my Qt installation has some limitation.
Below is what I got after adding "Pdf" to the find_package

C:\Users\Franco\Work\BioImp\Sources\CMakeLists.txt:51: error: Could not find a package configuration file provided by "Qt5Pdf" with any
of the following names:

  Qt5PdfConfig.cmake
  qt5pdf-config.cmake

Add the installation prefix of "Qt5Pdf" to CMAKE_PREFIX_PATH or set
"Qt5Pdf_DIR" to a directory containing one of the above files.  If "Qt5Pdf"
provides a separate development package or SDK, be sure it has been
installed.

Call stack:
  C:/Users/Franco/Work/BioImp/Sources/CMakeLists.txt:51 (find_package)
  C:/Qt/5.15.2/msvc2019_64/lib/cmake/Qt5/Qt5Config.cmake:28 (find_package)

jsulm

Then you did not install QtPdf module as others pointed out. Install it first.

franco.amato

It's not available for Qt5

jsulm

@franco-amato said in Alternative to poppler for converting a pdf document to QImage:

It's not available for Qt5

As was already pointed out by @Christian-Ehrlicher it is available since Qt 5.10.
What exact Qt version do you use?

franco.amato

I am using Qt 5.15.2
Could you show exactly from where it can be downloaded? Using the maintenance tool, it's available only for Qt 6

ChrisW67

@franco-amato Source-wise QPdfDocument is part of Qt Webengine. However, installing this module's binary from the installer does not deliver this class (at least on my Linux box). YMMV may vary on Windows.